1. Field of the Invention
This invention relates to the oxidative fluorination of various phenols by reaction with sulfur tetrafluoride in hydrogen fluoride solution. It also relates to certain novel fluorohydrocyclohexadienes, fluorohydrocyclohexadienones and perhalo-4-(perhalophenoxy)-2,5-cyclohexadienes that are useful as solvents and/or plasticizers for polymers.
2. Description of the Prior Art
No published reports of any reactions involving a phenol and sulfur tetrafluoride (SF.sub.4) are known. However, a number of examples of reaction between organic alcohols and SF.sub.4 are known, often with the result of replacing the hydroxyl with fluorine. Hydrogen fluoride (HF) is a well recognized catalyst for the replacement of carbonyl oxygen with two fluorines by means of SF.sub.4 (Smith, U.S. Pat. No. 2,859,245). Aliphatic, cycloaliphatic and aromatic compounds containing Cl and/or Br are disclosed to react with SF.sub.4 to replace Cl and Br with F using HF as a catalyst (Smith, U.S. Pat. No. 2,937,171). Carboxylic acids containing primary and secondary amino groups are successfully converted to corresponding trifluoromethyl amines in HF medium (Raasch, Jour. Org. Chem., vol. 27, p. 1406-1409, 1962).
Tetrachloro-p-quinone is reported to react with SF.sub.4 in the presence of HF to form 1,1,4,4-tetrafluorotetrachloro-2,5-cyclohexadiene and 4,4-difluoro-2,3,5,6-tetrachloro-2,5-cyclohexadien-1-one (Hasek et al., Jour. Am. Chem. Soc., Vol. 82, p. 543, 1960). ##STR3##
Likewise, tetrafluoro-p-quinone and 2,6-dichloro 3,5-difluoro-1,4-quinone are reported to give octafluoro-1,4-cyclohexadiene and 1,5-dichlorohexafluoro-1,4-cyclohexadiene, respectively (Shteingarts and Oksenenko, Jour. Org. Chem. (U.S.S.R.), Vol. 6, p. 1623, 1970). ##STR4##
Similarly, 9-keto-9,10-dihydroanthracene is reacted with SF.sub.4 in the presence of HF as catalyst to give 10,10-difluoro-9-keto-9,10-dihydroanthracene (Applequist and Searle, Jour. Org. Chem., vol. 29, p. 987, 1964). ##STR5##
Shteingarts et al. (Jour. Org. Chem., U.S.S.R., Vol. 37, p. 1537, 1967) show that pentafluoro-4-nitrocyclohexa-2,5-dien-1-one, formed by the action of nitrating agents on an excess of pentafluorophenol, on decomposing in an excess of the initial phenol, forms pentafluoro-4-(pentafluorophenoxy)cyclohexa-2,5-dien-1-one. ##STR6##